It seems that there’s an issue in the Xcode Archive step that is causing these errors. We’re working on the fix and will post back here once the new step version is deployed.
In the meantime the workaround is detailed in this blogpost: https://blog.bitrise.io/new-export-options-plist-in-xcode-9
Only important thing I’d add to the post is: when you do the export from Xcode, don’t select the Automatic option (see screenshot below).
